Switching & Routing Multilayer Switching IP Switching, MPLS

1. Switching & RoutingMultilayer SwitchingIP Switching, MPLS 1999. 7.7. ETRI, MPLS 시스템팀 전 병천 bcjeon@etri.re.kr

2. Contents • Internet Access Technologies and Requirements • QoS, VPN, Traffic Engineering • IP Switching, Tag Switching, MPLS • High-Speed Switching/Routing • Switching & Routing • Multilayer Stching • Technologies for IP Transport • IP over ATM • IP over SONET/SDH • IP over WDM

3. ISP Network Backbone Network Headend Carrier Network DSLAM Access Network Data Network (F/R,X.25) 광가입자 망 CATV PSTN/ISDN Leased Line F/R X.25 xDSL PSTN ISDN LAN Cable Modem Residential Business Leased Line F/R X.25 ADSL PSTN ISDN CATV 56K~155M 56K~2M ~56K ~155M 1M~8M ~56K ~128K 10~30M Network for Internet Access

4. Corporate Intranet Corporate Intranet Network Topology for Internet Access Telco Network Corporate Intranet PSTN Data Network (FR/ATM) xDSL ISP Network Access Server Mobile ISP POP - Residential User - Business User

5. Data Network Data Network 이용형태 - Internet access - Intranet 구축 56K~2Mbps Frame Relay ATM - Internet Access Server - DSLAM Access Router - Cable Modem Access Server - Remote Access Server(RAS) - Enterprise Access Router - ISP POP Network Provider Area 2~622Mbps FR-ATM Interworking - Network Interworking - Service Interworking

6. Case 2 ISP Network Network Service Provider FR/ATM/SONET/WDM Internet Service Provider Network • ATM based Data Service • Data Network • ISP Network • Access Protocol • ATM PVC • Classical IP over ATM • CSI(Carrier Scale Internetworking) • MPLS ISP Network Case 1 FR/ATM/SONET/WDM

7. ATM+IP related functions ATM only function IP Service Models Overlay Model o Traffic driven shortcut - QoS problem - Signaling overhead o Protocol - LANE, MPOA - IPOA, NHRP PVC Integrated Model o Topology/traffic driven shortcut - Closely related with ATM QoS - Minimize control overhead o Protocol - MPLS, I-PNNI, PAR

8. Internet Architecture • Single infrastructure based on IP • Richer applications • Lower cost of ownership • Aggressive cost/feature/ performance • Interoperability Data Voice Video IP Packet Transport ATM Transport SONET/WDM

9. Internet Evolution • Information Infrastructure for multiservice • Multiservice: data, voice, video • Requirements for business class internet • Security, privacy, authentication • Reliability for mission critical application • Uniform, expectable performance • Key technologies on the way • High Speed Switching/Routing • Scalability • High Degree of QoS(Quality of Service) • VPN(Virtual Private Network) • Traffic Engineering

10. VPN(Virtual Private Network) • Virtual Private Network • VPN provide a means of secure data transfer over a public or shared network • Types of VPN • Carrier class VPNs: Frame Relay, ATM, MPLS based VPN • IP VPN: IP based Tunneling • IP VPN Requirements • Security • QoS, Service Level Agreement(SLA) • Manageability(Administration & Policy based control) • Scalability

11. Traffic Engineering • Traffic Engineering Goals • Distribute flows over network resources • Try to avoid packet loss • Try to minimize queuing delay • Reduce transmission costs • Reduce network management labor costs • Requirements • Traffic monitoring & analysis • Fast reroute • VPN support • Dynamic load sensitivity ISP Backbone Edge router

12. Hard QoS Per flow RSVP or ATM request QoS at flow set up Flows can be carried over VCs that provide required QoS End-to end network protocol/algorithm RSVP, ATM connection Soft QoS Per class DiffServ DS bit is marked and checked per packet Flows can be grouped by source, dest., service class Node protocol/algorithm CoS marking, RED Queuing algorithm Class of Service QoS(Quality of Service) CoS(Class of Service)

13. Mechanisms for Providing QoS • Plentiful Capacity • High-capacity links • Fast processor • Plentiful buffers • Traffic Engineering • Reservation based • Admission control • Dynamic resource reservation • Congestion control • ATM, RSVP • Reservationless • Traffic classification • Priority based treatment • Differentiated Service

14. ATM QoS Mechanism • Virtual Circuit • Differentiate traffic and classify packets • Traffic policing per VC • Service Categories and Traffic/QoS Descriptors • Service categories: CBR, VBR, ABR and UBR • Traffic parameters: SCR, PCR, MBS, CTD, CDV • QoS Signaling & Routing • Signaling messages carry traffic and QoS characteristics • Hard-state reservation set up • Admission control • Intelligent Queuing Mechanisms • Per-VC queuing • Priority queuing & Weighted fair queuing

15. ATM QoS - UPC - Admission control - Usage based billing - Congestion control - Resource reservation - Traffic classification - Per-VC queuing - Priority queuing - Weighted fair queuing

16. Internet QoS Issues • Packet Classification • Admission Control • bandwidth Management • Traffic Shaping • Policing • Congestion Management • RED(Random Early Detection), WRED • Queue Management • Queuing • Scheduling

17. IP QoS - Packet classification - Admission control - Usage based billing - Congestion control - Resource reservation - Traffic classification - Per-flow queuing - Priority queuing - Weighted fair queuing

18. Separate VCs with ATM QoS for Each IP Traffic Class ATM Network Separate Labels with QoS for Each IP Traffic Class MPLS Network IP QoS to ATM QoS Interworking

19. ATM 기반 프로토콜 LANE 2.0 Multiple LES, BUS LANE 1.0 MPOA Layer 2+3, NHRP - Single LES, BUS - Layer 2 emulation - 적용 범위: single subnet - 종단간 ATM 가상연결 설정 - Layer 2, 3 동시지원 - 라우팅이가능한모든 영역지원 NHRP+Multicasting Classical IP over ATM IP over ATM + NHRP - Single ARP server - 적용 범위: single LIS - Multiple ARP, NHRP server - 라우팅이가능한모든 영역지원 - Multicasting

20. Integrated Protocol Integrated P-NNI - SVC 라우팅과IP 라우팅을동시에처리 - P-NNI 1.0 프로토콜적용 - LANE, MPOA와호환성유지 Integrated Routing LANE IP over ATM MPOA IP Switching, Tag Switching Integrated Switching - 스위칭과라우팅분리 - SVC를위한라우팅과 network 계층라우팅이중복 - 라우터 + ATM 스위치(IP Switch) - 에지 라우터 + 태그 스위치 - IP 라우팅프로토콜그대로적용

21. IP Switching, Tag SwitchingMultiprotocol Label Switching

22. IP Switching Peer Overlay Topology Address Resolution Flow MPOA IP Navigator Flow Gigabit IP VNS ARIS Tag Switching CSR/FANP Gigabit+Routers L3 Switch IFMP/GSMP MARS NHRP Classical IP RFC1483 PVC MPLS A Taxonomy of IP Switching Solutions • Different environment warrant different solutions • Factors:scalability,cost,simplicity,extensibility, etc

23. Enterprise IP Switching Alternatives

24. IP Switch Controller GSMP(General Switch Management Protocol) ATM Switch Upstream Node Downstream Node IFMP(Ipsilon Flow Management Protocol) IP Switching Protocol • GSMP(RFC1987) • 호설정, 해제, 연결상태 관리에 관련된 기능 수행 • 어느 ATM 스위치도 GSMP를 수행하면 IP 스위치 수행 가능 • IFMP(RFC1953) • 타 IP 스위치 또는 호스트간 프로토콜 • Flow redirection message 전달

25. IP Switch Controller IP Switch Controller ATM Switch ATM Switch Upstream Node Downstream Node Upstream Node Downstream Node IP Switch Controller IP Switch Controller ATM Switch ATM Switch Upstream Node Downstream Node Upstream Node Downstream Node IP Switch Operation 1. Default operation 2. Flows upstream labeled 3. Flows downstream labeled 4. Cut-through switching Ref. "IP Switching" Ipsilon networks

26. Flow Classification in the IP Switch

27. 가상채널 IP 스위치 A-a A-b A-c R1 R2 LAN-1 LAN-2 A ATM 망 a b c IP Switch의 문제점 • 가상채널이 과다하게 필요 • 동일 경로상에 다수의 가상채널이 설정됨 • 동일 경로라도 트래픽 흐름마다 가상채널 생성 • 트래픽 제어 • 데이터 망에서는 버퍼 필요

28. In Address Out Out Tag Prefix I’face Tag X 128.89 2 4 X 171.69 2 5 In Address Out Out Tag Prefix I’face Tag 4 128.89 0 9 5 171.69 1 7 171.69 1 1 2 0 3 4 128.89.25.4 Data 128.89.25.4 Data 128.89.25.4 Data 9 128.89.25.4 Data 128.89 Tag Switching Example

29. Traffic classification e.g. by customer, application, protocol One tag per precedence level Premium, Gold, Standard Data PREC TOS Tag CoS Setup

30. In Address Out Out Tag Prefix I’face Tag X 176.69 1 4 X 171.69 1 5 In In Prec Address Out Out I’face Tag Prefix I’face Tag 4 4 0 171.69 1 9 5 5 1 171.69 1 7 2 9 1 171.69 1 7 Prec 0 1 1 1 3 1 171.69 2 Edge TSR asks for different tags for different precedences Tag QOS:Precedences

31. QOS and Tags Standard Routing Protocols TDP+precedences, or RSVP+tags Routing Tag Information Base(TIB) Per-Tag QOS Mechanisms Tag Edge Router Tag Edge Router Tag Switch

32. What is MPLS ? Packet forwarding by router Host B Host A Router Router Router Router Packet forwarding by label switch Label Switch Label Switch Host B Ingress Node Egress Node Host A - Label assignment - Forwarding classification - Forwarding based on label - Label swapping - Label removal - Label distribution

33. MPLS Network Architecture Label Switch Router (LSR) • Switching on Label • Label swapping MPLS Domain LER Label Edge Router (LER) MPLS Control Component LER • Full-function Layer 3 routers • Label Binding based on FIB ATM Switch Fabric

34. Goals of Multiprotocol Label Switching • MPLS extends traditional IP in the following areas: • Simplified Forwarding • Based on labels instead of longest prefix-match • Efficient Explicit Routing • Route is specified once by source at path setup time • Traffic Engineering • Split traffic load over multiple parallel or alternate routes • QoS Routing • Select routes based upon QoS requirements • Non-trivial Mappings of IP Datagrams onto Paths • Performed only at network edges/borders

35. Relationship Between MPLS and ATM • MPLS is being designed to explicitly allow Label Switching Routers (LSRs) to be based on: • Traditional router platforms • ATM switch platforms • ATM pioneered many of the basic underlying building blocks for Simplified Forwarding, Explicit Routing, Traffic Engineering, andQoS Routing. • MPLS and MPLS devices must inevitably incorporate these building blocks and further build upon them.

36. OUT prefix (24) Cos(3) Label (20) Stack(1) Label Encoding • MPLS specific hardware • Generic MPLS encapsulation • ATM switches as LSRs • SVC encoding: Use VPI/VCIas a label • SVP encoding: Use VPIas a top label stackUse VCIas a secondlabel • SVP multipoint encoding: VPI => top label stackVCI => second labelRemained VCI => ingress Experimental Use Label(20 bits) Exp(3) S(1) TTL(8bits) Bottom of stack

37. Signaling Signaling LDP LDP IP over ATM & MPLS IP over ATM Upper Upper UNI 3.1 PNNI/B-ISUP UNI 3.1 IP IPOA MPOA IPOA MPOA IP ATM ATM Traffic based VC setup(Signaling) LER LER MPLS Upper Upper LSR LSR LDP/OSPF LDP/OSPF LDP/OSPF IP MPLS MPLS IP ATM ATM Topology based LSP Setup(LDP)

38. MPLS IPOA Routing 인접 노드간에만 라우팅 정보 교환 모든 에지노드와 라우팅 정보 교환 Forwarding 라우팅 오버헤드 감소(확장성) Scalability of MPLS 3계층 2계층

39. Label Assignment • Topology driven label assignment • By normal processing of routing protocol control traffic [OSPF, BGP] • Labels are pre-assigned (in the general case) • Request driven label assignment • By the processing of request based control traffic [RSVP] • LSRs process control traffic load only • Traffic driven label assignment • By the arrival of data at an LSR • Label assignment and distribution according to traffic patterns

40. VPN 대안 비교 • Comparison of ATM, MPLS, and IP VPNs

41. MPLS 기반 VPN 서비스 • 경제적인 VPN 서비스 가능 • VPN 솔루션별 총 소요비용 절감비율(출처:양키그룹) • 테라비트라우터: 5% • MPLS: 6% • VPN 솔루션별 망운영비용 절감비율 • 테라비트라우터: 11% • MPLS: 17% • ATM VPN과 IP-VPN 서비스 통합 제공 • 하나의 망으로 2가지 VPN 서비스 동시 제공 • ATM 망 사업자에게 적합한 VPN 솔루션 • 기업 규모, 요구별 다양한 VPN 서비스 제공

42. ATM 교환기 기반 LSR LDP Information Signaling Information Signaling ATM Switch Fabric MPLS Resource Mgm. Line Interface

43. ATM 기반 MPLS Protocol Routing Protocol (OSPF, BGP) LDP FIB VC Manager TCP/IP GSMP Master ATM Interface Switch Control Interface Label path ATM Switch GSMP Slave FIB: Forwarding Information Base GSMP: General Switch Management Protocol CMB: Connection Management Block CMB

44. LSR/LER 구성 • 표준화된 스위치 제어 인터페이스를 적용 • 교환기와 독립적으로 개발 • 개발 기간 단축 • 교환기 Dependent Part • CCCP 호처리 블록과 GSMP 연동 기능 • 라우팅 모듈 관리 기능 • 교환기 Independent Part • 라우팅 모듈 • LER: IP forwarding, LDP 처리H/W + S/W • LSR: LDP 처리S/W만으로 처리 가능 SIM Switch Fabric SIM .. …. SIM .. SIM SIM CMDH 155M 622M Call Control GSMP LDP OSPF/BGP TCP/IP Resource Management AAL5 GSMP/VSI Control path CCCP 추가 기능

45. Switching & Routing

46. Switch Technology Evolution IP Switching MPLS Tag Switching IP Navigator MPLS TagSwitching IP Navigator Internet Computing IP Switching MPLS SecureFast FastIP Routing Switches 802.1Q LANE MPOA Propritary CUT-Through CUT-Through Cell Based Packet-by-Packet VLANs Frame Based Workgroup Client/Server Computing Store&Forward/ Cut Through Layer 3 Switches Layer 2 Switches Mainframe Computing LAN Focus WAN Focus Bridges Routers

47. Switching & Routing Basic Features Additional Features Switching (Layer 2) - Packet by packet switching in hardware - Wire speed performance - LAN switch(MAC address) - ATM switch(VPI/VCI) - Load balancing - VLAN(IEEE 802.1p) - QoS feature(802.1q) - Protocol filtering Routing (Layer 3) - Route processing (RIP, OSPF, DVMRP) - Packet forwarding(IP, IPX) - Packet filtering - Flow control - Policy enabler - QoS feature(packet classification) . RED, WRED . Scheduling(WFQ etc) - Firewall

48. LAN Switching Technologies ATM switching - LAN Emulation - MPOA Shared media - CSMA/CD - Token Ring LAN switching L2/L3 switching - Layer 2 switching - VLAN - Switching + Routing - Layer 3 switching - Layer 4 handling - High speed - Large network - Filtering of broadcasting traffic - Virtual LAN - Intelligence

49. Edge Core Layer2 Layer 4 Maximizing network throughput Meeting app & VON needs Definition : Multi_layer Switches IP application optimized networking by - High performance switching - Layer2 and/or Layer 4+function

50. Router vs. Layer 3 Switch Router Layer 3 switch Protocol Multiprotocol IP/IPX Interface - Multiple media interface LAN: Ethernet, Token ring FDDI WAN: FR, ATM, SONET HSSI - Ethernet interface only 10M, 100M, 1Gbps Routing - Full routing protocol RIP, OSPF, BGP, PIM EIGRP - RIP, DVMRP may be OSPF QoS feature - Robust QoS - Simple QoS